Since 90% of my dialogue is a combination of non-sequiturs and one liners this happens to me from time to time. Usually one of my friends will, after a short pause, say "Anyways..." and continue with a different conversation and we quietly let the joke die. Other times i'll, after a short pause, make the "They can't all be winners." comment before changing the subject.

You fail a joke, the group is dead silent, you're turning red and are about to die from awkwardness.

What do you do?

Fail another joke, eventually the level of fail clicks with everyone and they just assume you have a really shitty sense of comic timing in which case you're either forgiven or ostracized for life. IF the latter... fail a third joke and see what happens. If you're a hot chick dismiss this, since guys won't care if you're funny or not. Just bend forward and smile at the nearest schmuck [you make eye contact with] and watch him become the center of attention instead of you.

Glare at the closest friend and wait for him to solve the problem...if that fails...hit him.

Oh this is rich. LMAO. I can totally picture me doing that to my bestie. XD

Anyway, I usually just shrug that awkward moment off. Eventually someone will pop up another question to get the conversation back in gear, so I just shamelessly join in. It helps that I have the abnormal ability to be shameless in such times.